[PATCH v2 2/3] taint: Consolidate documentation

From: Kees Cook
Date: Mon Feb 19 2018 - 18:53:32 EST


This consolidates the taint bit documentation into a single place with
both numeric and letter values. Additionally adds the missing TAINT_AUX
documentation.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
Documentation/sysctl/kernel.txt | 53 +++++++++++++++++++++--------------------
kernel/panic.c | 23 ++++--------------
2 files changed, 31 insertions(+), 45 deletions(-)

diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 412314eebda6..4a890c7fb6c3 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -964,32 +964,33 @@ detect a hard lockup condition.

tainted:

-Non-zero if the kernel has been tainted. Numeric values, which
-can be ORed together:
-
- 1 - A module with a non-GPL license has been loaded, this
- includes modules with no license.
- Set by modutils >= 2.4.9 and module-init-tools.
- 2 - A module was force loaded by insmod -f.
- Set by modutils >= 2.4.9 and module-init-tools.
- 4 - Unsafe SMP processors: SMP with CPUs not designed for SMP.
- 8 - A module was forcibly unloaded from the system by rmmod -f.
- 16 - A hardware machine check error occurred on the system.
- 32 - A bad page was discovered on the system.
- 64 - The user has asked that the system be marked "tainted". This
- could be because they are running software that directly modifies
- the hardware, or for other reasons.
- 128 - The system has died.
- 256 - The ACPI DSDT has been overridden with one supplied by the user
- instead of using the one provided by the hardware.
- 512 - A kernel warning has occurred.
-1024 - A module from drivers/staging was loaded.
-2048 - The system is working around a severe firmware bug.
-4096 - An out-of-tree module has been loaded.
-8192 - An unsigned module has been loaded in a kernel supporting module
- signature.
-16384 - A soft lockup has previously occurred on the system.
-32768 - The kernel has been live patched.
+Non-zero if the kernel has been tainted. Numeric values, which can be
+ORed together. The letters are seen in "Tainted" line of Oops reports.
+
+ 1 (P): A module with a non-GPL license has been loaded, this
+ includes modules with no license.
+ Set by modutils >= 2.4.9 and module-init-tools.
+ 2 (F): A module was force loaded by insmod -f.
+ Set by modutils >= 2.4.9 and module-init-tools.
+ 4 (S): Unsafe SMP processors: SMP with CPUs not designed for SMP.
+ 8 (R): A module was forcibly unloaded from the system by rmmod -f.
+ 16 (M): A hardware machine check error occurred on the system.
+ 32 (B): A bad page was discovered on the system.
+ 64 (U): The user has asked that the system be marked "tainted". This
+ could be because they are running software that directly modifies
+ the hardware, or for other reasons.
+ 128 (D): The system has died.
+ 256 (A): The ACPI DSDT has been overridden with one supplied by the user
+ instead of using the one provided by the hardware.
+ 512 (W): A kernel warning has occurred.
+ 1024 (C): A module from drivers/staging was loaded.
+ 2048 (I): The system is working around a severe firmware bug.
+ 4096 (O): An out-of-tree module has been loaded.
+ 8192 (E): An unsigned module has been loaded in a kernel supporting module
+ signature.
+ 16384 (L): A soft lockup has previously occurred on the system.
+ 32768 (K): The kernel has been live patched.
+ 65536 (X): Auxiliary taint, defined and used by for distros.

==============================================================

diff --git a/kernel/panic.c b/kernel/panic.c
index c5e0fd5a188e..15d333a54ece 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -328,27 +328,12 @@ const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
};

/**
- * print_tainted - return a string to represent the kernel taint state.
+ * print_tainted - return a string to represent the kernel taint state.
*
- * 'P' - Proprietary module has been loaded.
- * 'F' - Module has been forcibly loaded.
- * 'S' - SMP with CPUs not designed for SMP.
- * 'R' - User forced a module unload.
- * 'M' - System experienced a machine check exception.
- * 'B' - System has hit bad_page.
- * 'U' - Userspace-defined naughtiness.
- * 'D' - Kernel has oopsed before
- * 'A' - ACPI table overridden.
- * 'W' - Taint on warning.
- * 'C' - modules from drivers/staging are loaded.
- * 'I' - Working around severe firmware bug.
- * 'O' - Out-of-tree module has been loaded.
- * 'E' - Unsigned module has been loaded.
- * 'L' - A soft lockup has previously occurred.
- * 'K' - Kernel has been live patched.
- * 'X' - Auxiliary taint, for distros' use.
+ * For individual taint flag meanings, see Documentation/sysctl/kernel.txt
*
- * The string is overwritten by the next call to print_tainted().
+ * The string is overwritten by the next call to print_tainted(),
+ * but is always NULL terminated.
*/
const char *print_tainted(void)
{
--
2.7.4